Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for Triangulum Pinwheel: 06-04 (2), 06-05 (2), 06-06 (2), 06-07 (2), 06-08 (2) — by astronomy; check the weather when the night is within four days.

2044-05-11astronomy score per night — click a bar for that night2044-06-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-05-11 Wed	0	—	unknown	—	79.2° 11:35	5.76	100%	157.2°
2044-05-12 Thu	0	—	unknown	—	79.2° 11:30	5.7	99%	147.5°
2044-05-13 Fri	0	—	unknown	—	79.2° 11:25	5.65	96%	136.8°
2044-05-14 Sat	0	—	unknown	—	79.2° 11:25	5.6	92%	125.8°
2044-05-15 Sun	0	—	unknown	—	79.2° 11:20	5.54	86%	114.5°
2044-05-16 Mon	0	—	unknown	—	79.2° 11:15	5.49	79%	103.2°
2044-05-17 Tue	0	—	unknown	—	79.2° 11:10	5.44	71%	91.8°
2044-05-18 Wed	0	—	unknown	—	79.2° 11:05	5.39	62%	80.2°
2044-05-19 Thu	0	—	unknown	—	79.2° 11:05	5.34	52%	68.5°
2044-05-20 Fri	0	—	unknown	—	79.2° 11:00	5.29	42%	56.5°
2044-05-21 Sat	0	—	unknown	—	79.2° 10:55	5.24	32%	44.5°
2044-05-22 Sun	0	—	unknown	—	79.2° 10:50	5.19	23%	32.5°
2044-05-23 Mon	0	—	unknown	—	79.2° 10:45	5.14	14%	21.6°
2044-05-24 Tue	0	—	unknown	—	79.2° 10:45	5.1	7%	15.7°
2044-05-25 Wed	0	—	unknown	—	79.2° 10:40	5.05	2%	20.8°
2044-05-26 Thu	0	—	unknown	—	79.2° 10:35	5.01	0%	32.5°
2044-05-27 Fri	0	—	unknown	—	79.2° 10:30	4.97	1%	46.2°
2044-05-28 Sat	1	—	unknown	—	79.2° 10:30	4.92	5%	60.4°
2044-05-29 Sun	1	—	unknown	—	79.2° 10:25	4.88	11%	74.7°
2044-05-30 Mon	1	—	unknown	—	79.2° 10:20	4.85	20%	88.9°
2044-05-31 Tue	1	—	unknown	—	79.2° 10:15	4.81	30%	102.7°
2044-06-01 Wed	1	—	unknown	—	79.2° 10:10	4.77	41%	116.0°
2044-06-02 Thu	1	—	unknown	—	79.2° 10:10	4.74	52%	128.8°
2044-06-03 Fri	1	—	unknown	—	79.2° 10:05	4.7	62%	141.0°
2044-06-04 Sat	2	—	unknown	04:30–04:35 (marginal, 0.08 h)	79.2° 10:00	4.67	72%	152.1°
2044-06-05 Sun	2	—	unknown	04:30–04:35 (marginal, 0.08 h)	79.2° 09:55	4.64	80%	161.0°
2044-06-06 Mon	2	—	unknown	04:25–04:30 (marginal, 0.08 h)	79.2° 09:50	4.62	88%	164.3°
2044-06-07 Tue	2	—	unknown	04:20–04:30 (marginal, 0.17 h)	79.2° 09:50	4.59	93%	159.3°
2044-06-08 Wed	2	—	unknown	04:20–04:30 (marginal, 0.17 h)	79.2° 09:45	4.56	97%	150.1°
2044-06-09 Thu	2	—	unknown	04:20–04:30 (marginal, 0.17 h)	79.2° 09:40	4.54	99%	139.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-05-11&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.